Nockels C F, Ewing D L, Phetteplace H, Ritacco K A, Mero K N
J Nutr. 1984 Sep;114(9):1733-6. doi: 10.1093/jn/114.9.1733.
The effect of a marginal vitamin A deficiency on thyroid function was investigated in chicks gaining weight. This study examined the hypothesis that hypothyroidism is one of the earliest manifestations of hypovitaminosis A in chicks. Day-old Leghorn cockerels were fed vitamin A-adequate and deficient diets. Blood vitamin A levels were reduced in the deficient chicks by 3 weeks of age. Body weight gains were less in the 5-, 6-, 7- and 8-week-old A-deficient chicks than in controls. Compared to controls, vitamin A-deficient chicks were characterized by thyroid follicle hypertrophy by 4 weeks, heavier thyroids as a percent of body weight at 5 weeks, less serum thyroxine (T4) at 7 weeks and lower serum triiodothyronine (T3) and T4 at 8 weeks. These results indicate that one of the earliest signs of vitamin A deficiency in chicks is hypothyroidism.
研究了边缘性维生素A缺乏对体重增加的雏鸡甲状腺功能的影响。本研究检验了甲状腺功能减退是雏鸡维生素A缺乏症最早表现之一的假说。给1日龄的来航公鸡饲喂维生素A充足和缺乏的日粮。到3周龄时，缺乏组雏鸡的血液维生素A水平降低。5、6、7和8周龄的维生素A缺乏雏鸡的体重增加低于对照组。与对照组相比，维生素A缺乏雏鸡在4周时表现为甲状腺滤泡肥大，5周时甲状腺重量占体重的百分比更高，7周时血清甲状腺素（T4）减少，8周时血清三碘甲状腺原氨酸（T3）和T4降低。这些结果表明，雏鸡维生素A缺乏的最早迹象之一是甲状腺功能减退。
